Shielding Plate Wave Propagation for OAM Isolation
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Solution Overview
Problem
In OAM multiplexing transmission technology, ensuring isolation between streams in a matrix circuit over a broadband frequency range is challenging, particularly when using a two-dimensional array antenna, leading to decreased transmission capacity and increased size and complexity of the apparatus.
Innovation Solution
A circuit design incorporating a first and second microstrip line with a 90-degree hybrid circuit and delay line, a shielding plate with opening portions to propagate electromagnetic waves between the microstrip lines, and amplifiers to adjust amplitude, while maintaining a compact and efficient configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a Butler matrix circuit is used to ensure isolation between streams in OAM multiplexing transmission, then transmission capacity is improved, but the isolation between streams deteriorates over broadband frequency range
Solution Approach 1:
The patent transitions from a planar two-dimensional array antenna to a three-dimensional spherical array antenna configuration. This dimensional change enables the use of spherical harmonics for signal processing, which provides better isolation between OAM streams across broadband frequencies by exploiting the three-dimensional spatial structure rather than being constrained to a flat plane.
Solution Approach 2:
The patent changes the fundamental parameters of the antenna system by adopting spherical coordinates and spherical harmonics instead of planar coordinates. This parameter transformation allows the system to maintain stream isolation over broadband frequency ranges by matching the natural spherical wave propagation characteristics of electromagnetic waves.
2Productivity
If a Butler matrix circuit with multiple input and output terminals is used, then multi-stream transmission is enabled, but the size and complexity of the apparatus increases
Solution Approach 1:
The patent replaces the complex mechanical Butler matrix circuit with an electromagnetic field-based spherical array antenna system. Instead of using physical matrix circuits with multiple terminals and delay lines, the invention uses spherical harmonics transformation to achieve multi-stream transmission, significantly reducing apparatus complexity while maintaining the capability to handle multiple streams simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively suppresses the decrease in isolation between streams and reduces the size of the wireless communication apparatus, achieving both high-speed transmission and compactness.
Implementation Method 1
a shielding plate including an opening portion. The shielding plate causes a current, a voltage, or an electromagnetic wave directed from one end of the first microstrip line, which has the opened tip, toward the shielding plate to propagate to one end of the second microstrip line, which has the opened tip, through the opening portion
Data Source
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AI summary
A circuit includes a first input and output unit to which a current, a voltage, or an electromagnetic wave (referred to as "current or the like" below) is applied, a second input and output unit to which the current or the like is applied, a first board including a matrix circuit which is formed by a first line and includes a 90-degree hybrid circuit and a delay line, the first line in which one end is connected to the first input and output unit and a tip of the other end is opened, a second board including a second line in which one end is connected to the second input and output unit, and a tip of the other end is opened, and a shielding plate including an opening portion. The shielding plate causes the current or the like directed from one end of the first line, which has the opened tip, toward the shielding plate to propagate to one end of the second line, which has the opened tip, through the opening portion. In addition, the shielding plate causes the current or the like directed from the one end of the second line, which has the opened tip, toward the shielding plate to propagate to the one end of the first line, which has the opened tip, through the opening portion.